ATLAS search for a heavy gauge boson decaying to a charged lepton and a neutrino in $pp$ collisions at $\sqrt{s}=7$ TeV
The ATLAS detector at the LHC is used to search for high-mass states, such as heavy charged gauge bosons (W'), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of pp collisions at a centre-of-mass energy of 7 TeV corresponding to an integrated luminosity of 4.7 fb-1. No excess beyond Standard Model expectations is observed. A W' with Sequential Standard Model couplings is excluded at the 95% credibility level for masses up to 2.55 TeV. Excited chiral bosons (W*) with equivalent coupling strength are excluded for masses up to 2.42 TeV.
20 September 2012
Contact: Exotics conveners
internal
Figures
Figure 01a
Reconstructed electron eta distributions for W'->enu and W*->enu wth m_W' = 2.0 TeV. All distributions are normalised to unit area.
png (76kB) eps (432kB) pdf (14kB)
Figure 01b
Reconstructed electron mT distributions for W'->enu and W*->enu wth m_W' = 2.0 TeV. All distributions are normalised to unit area.
png (63kB) eps (428kB) pdf (10kB)
Figure 02a
Spectra of charged lepton pT for the electron channel for events with mT > 200 GeV after event preselection. The points represent data and the filled histograms show the stacked backgrounds. Open histograms are W'->lnu signals added to the background with masses in GeV indicated in parentheses in the legend. The QCD backgrounds estimated from data are also shown. The signal and other background samples are normalised using the integrated luminosity of the data and the NNLO (approximate-NNLO for ttbar) cross sections listed in Table 1.
png (18kB) eps (420kB) pdf (12kB)
Figure 02b
Spectra of charged lepton pT for the muon channel for events with mT > 200 GeV after event preselection. The points represent data and the filled histograms show the stacked backgrounds. Open histograms are W'->lnu signals added to the background with masses in GeV indicated in parentheses in the legend. The QCD backgrounds estimated from data are also shown. The signal and other background samples are normalised using the integrated luminosity of the data and the NNLO (approximate-NNLO for ttbar) cross sections listed in Table 1.
png (18kB) eps (422kB) pdf (13kB)
Figure 02c
Spectra of missing ET for the electron channel for events with mT > 200 GeV after event preselection. The points represent data and the filled histograms show the stacked backgrounds. Open histograms are W'->lnu signals added to the background with masses in GeV indicated in parentheses in the legend. The QCD backgrounds estimated from data are also shown. The signal and other background samples are normalised using the integrated luminosity of the data and the NNLO (approximate-NNLO for ttbar) cross sections listed in Table 1.
png (18kB) eps (420kB) pdf (12kB)
Figure 02d
Spectra of missing ET for the muon channel for events with mT > 200 GeV after event preselection. The points represent data and the filled histograms show the stacked backgrounds. Open histograms are W'->lnu signals added to the background with masses in GeV indicated in parentheses in the legend. The QCD backgrounds estimated from data are also shown. The signal and other background samples are normalised using the integrated luminosity of the data and the NNLO (approximate-NNLO for ttbar) cross sections listed in Table 1.
png (18kB) eps (420kB) pdf (12kB)
Figure 02e
Spectra of mT for the electron channel for events with mT > 200 GeV after event preselection. The points represent data and the filled histograms show the stacked backgrounds. Open histograms are W'->lnu signals added to the background with masses in GeV indicated in parentheses in the legend. The QCD backgrounds estimated from data are also shown. The signal and other background samples are normalised using the integrated luminosity of the data and the NNLO (approximate-NNLO for ttbar) cross sections listed in Table 1.
png (18kB) eps (419kB) pdf (12kB)
Figure 02f
Spectra of mT for the muon channel for events with mT > 200 GeV after event preselection. The points represent data and the filled histograms show the stacked backgrounds. Open histograms are W'->lnu signals added to the background with masses in GeV indicated in parentheses in the legend. The QCD backgrounds estimated from data are also shown. The signal and other background samples are normalised using the integrated luminosity of the data and the NNLO (approximate-NNLO for ttbar) cross sections listed in Table 1.
png (18kB) eps (419kB) pdf (12kB)
Figure 03a
Expected and observed limits on sigma*B for W'->lnu in the electron channel. The calculated value for sigma*B (NNLO) and its uncertainty is also shown.
png (20kB) eps (519kB) pdf (21kB)
Figure 03b
Expected and observed limits on sigma*B for W*->lnu in the electron channel. The calculated value for sigma*B (LO) and its uncertainty is also shown.
png (19kB) eps (501kB) pdf (14kB)
Figure 03c
Expected and observed limits on sigma*B for W'->lnu in the muon channel. The calculated value for sigma*B (NNLO) and its uncertainty is also shown.
png (20kB) eps (519kB) pdf (21kB)
Figure 03d
Expected and observed limits on sigma*B for W*->lnu in the muon channel. The calculated value for sigma*B (LO) and its uncertainty is also shown.
png (20kB) eps (502kB) pdf (14kB)
Figure 03e
Expected and observed limits on sigma*B for W'->lnu in the combination of electron and muon channels assuming the same branching fraction for both. The calculated value for sigma*B (NNLO) and its uncertainty is also shown.
png (20kB) eps (519kB) pdf (21kB)
Figure 03f
Expected and observed limits on sigma*B for W*->lnu in the combination of electron and muon channels assuming the same branching fraction for both. The calculated value for sigma*B (LO) and its uncertainty is also shown.
png (20kB) eps (501kB) pdf (14kB)
Figure 04
Normalised cross-section limits (sigma_limit/sigma_SSM) for W'->lnu as a function of mass for this measurement and from CDF, CMS and the previous ATLAS search. The cross-section calculations assume the W' has the same couplings as the SM W-boson. The region above each curve is excluded at the 95% CL.
png (18kB) eps (393kB) pdf (11kB)
Auxiliary material
Figure 01
Normalised cross-section limits (sigma_limit/sigma_SSM) for W'->lnu as a function of mass for this measurement and from CDF and the previous ATLAS search. The cross-section calculations assume the W' has the same couplings as the SM W-boson. The region above each curve is excluded at the 95% CL.
png (16kB) eps (391kB) pdf (11kB)
